1. Field of the Invention
The present invention is directed to improvements in nonwoven fabric materials, especially those useful for manufacture of recreational products such as tents, outer wear, tarpaulins and the like. While nonwoven fabrics designed for such purposes have been available, their use has, in general, involved a decision between expensive, sophisticated laminates and simple single layer materials of rather limited utility. Reasons for the rather unsatisfactory choice include the demanding requirements for such a fabric which must be resistant to the passage of water, breathable, and flame retardant while also resistant to degradation by ultraviolet radiation. While much effort has been directed to achieving an optimum combination of these properties in a base material, the results to date have not been entirely satisfactory. For example, it has been found in many cases that treatments for flame retardancy and resistance to degradation by ultraviolet radiation detrimentally affect each other with the result that a compromise in these properties is necessary. In addition, it is desirable to provide such materials on a more economic basis while retaining beneficial properties. Therefore, the need persists for an improved nonwoven fabric especially intended for recreational uses.
2. Description of the Prior Art
Representative of prior art materials described generally above include those disclosed in U.S. Pat. No. 4,194,041 to Gore et al. dated Mar. 18, 1980. These laminates include a combination of a hydrophilic interior interfacing layer and a hydrophobic outer layer. Examples of the former include perfluorosulfonic ion exchange membranes and an example of the latter is polytetrafluoroethylene sheeting. Such materials are relatively costly, and the patent contains no disclosure of ultraviolet radiation degradation or flame retardancy results. U.S. Pat. No. 4,041,203 to Brock et al. issued Aug. 9, 1977 discloses laminates of spunbonded and meltblown nonwovens including a suggestion that such laminates may be useful for a wide variety of applications including outer wear linings, jackets, rainwear, pillow cases, sleeping and slumber bags and liners. The patent further suggests that water repellency and air permeability are attained and that pigments may be added for desired color effects. However, the patent does not disclose treatments for flame retardancy and ultraviolet radiation degradation resistance. U.S. Pat. No. 4,196,245 to Kitson et al. dated Apr. 1, 1980 also discloses laminates of spunbonded and meltblown nonwovens having liquid strike-through resistance and air permeability. U.S. Pat. No. 3,932,682 to Loft et al. dated Jan. 13, 1976 describes recreational fabric material having a capability of transmitting air and moisture vapor and being waterproof made by spray spinning a filamentary polymer material onto open-celled polymer film or noncellular elastic polymer film having been stretched and heat set. U.S. Pat. No. 4,217,386 to Arens et al. dated Aug. 12, 1980 describes laminates of meltblown and spunbonded webs with an activated carbon layer for garments to protect against toxic chemical vapors. U.S. Pat. No. 4,196,245 to Kitson et al. dated Apr. 1, 1980 describes a wide variety of laminates including at least two meltblown layers particularly useful for surgical applications. In addition, there are a great number of prior art patents describing processes for attaining one or more of the desired properties of flame retardancy, ultraviolet radiation degradation resistance, water repellency, and the like. Representative of these are U.S. Pat. No. 4,094,943 to Howarth et al. issued June 13, 1978, U.S. Pat. No. 3,955,028 to Weil issued May 4, 1976, U.S. Pat. No. 3,955,029 to Garner issued May 4, 1976, U.S. Pat. No. 4,035,542 to Rosenthal et al. issued July 12, 1977, U.S. Pat. No. 4,219,605 to Rohringer issued Aug. 26, 1980, U.S. Pat. No. 4,154,890 to Wagner issued May 15, 1979, U.S. Pat. No. 4,158,077 to Mischutin issued June 12, 1979, U.S. Pat. No. 4,178,408 to Franz et al. issued Dec. 11, 1979, U.S. Pat. No. 3,928,504 to Koelewijn issued Dec. 23, 1975, and U.S. Pat. No. 3,678,136 to Vandenberg issued July 18, 1972.